Reply: Do Self-Reports Reliably Assess Abstinence in Cocaine-Dependent Patients?

A double-blind, placebo-controlled trial of modafinil for cocaine dependence

“…Since we found poor concordance between patient self-reports and our objective UDS measure of abstinence, which is consistent with our prior experience (Dackis et al, 2005), we focused exclusively on the UDS results. Our primary analysis of the 24 UDS indicators was based on missing samples being imputed as cocaine positive.…”

“…Additional clinical and psychosocial characteristics were assessed at baseline and three follow-up meetings with the Addiction Severity Index (ASI) (McLellan et al, 1992), Hamilton Rating Scale of Anxiety (Ham A) (Hamilton, 1969), Hamilton Rating Scale of Depression (Ham D) (Hamilton, 1967), Beck Depression Inventory (BDI) (Beck et al, 1974) and the Symptom Checklist 90-Revised (SCL90-R) (Derogatis, 1977). We based the number of patients in each group on previous NIDA cocaine studies and the effect size of our earlier modafinil pilot study (Dackis et al, 2005). …”

“…We conducted a randomized, controlled pilot study (n=62) in “pure” cocaine dependent patients (i.e., those lacking other substance dependence except nicotine) and reported that patients treated with modafinil (400 mg/day) attained significantly more cocaine abstinence (p<0.03) according to objective urine BE testing (Dackis et al, 2005). The modafinil-treated patients also attained significantly longer periods of abstinence (p<0.05) than those treated with placebo.…”

“…Despite its ability to block the DAT and increase dopamine levels in reward circuits, the abuse potential of modafinil is limited by slow onset after oral administration, and its instability at high temperatures and relative insolubility in water makes modafinil unsuitable for intrapulmonary and intravenous administration. We carefully monitored the abuse potential of modafinil in our prior trial by analyzing the pill return rates of our subjects who were provided with extra pills each week in case they missed a study session, and there was no difference in pill return rates between the modafinil and placebo treated subjects (Dackis et al, 2005). These considerations suggest that modafinil does not have significant abuse potential and can be safely administered to cocaine dependent patients.…”

Reward-Related Dorsal Striatal Activity Differences between Former and Current Cocaine Dependent Individuals during an Interactive Competitive Game

“…While self-reported weekly spending in the FCD group is considerably higher than the CCD group, we believe that this difference might, at least in part, reflect under-reporting by the CCD group. A study by Harrison and Hughes [72] found that, with respect to recent cocaine users (i.e., the CCD group), “over the course of the 17-week clinical trial, subjects reported cocaine use on 20 percent of occasions, but tested positive for cocaine (qualitatively) on 68 percent of occasions.” Similar studies on self-reported usage in current cocaine abusers have also shown that such users tend to under-report [73], [74], [75]. Therefore, we speculate that many of the CCD individuals in our study may have been under-reporting their current usage.…”